The protagonist is a bit of a scumbag, and the first and third persons are constantly changing and attacking each other.
The protagonist is a loser in the 21st century. Because he was selected by the cheating system and sucked into the binary world, he can only go home after completing the task.
However, the system only issued a task and ignored him. This task was to become a good friend of Steve Rogers and accumulate 10,000 friendship points.
So, Captain America, let's be friends!